The paper argues for the relevance of Plato's Timaeus (especially 90b1-d7) for Chrysippus's theory of telos. It claims that Chrysippus could work out quite a few of his own ideas on the subject through a preliminary dialectical discussion of the Timaeus. Moreover, Chrysippus had good reasons, even from a generally anti-Platonic standpoint, to assimilate some aspects of the Platonic stance in his theory of telos. A parallel analysis also shows that despite the strong correspondences, the most significant difference between the Platonic and the Stoic positions lies in the cognitive content of the cosmological knowledge required for achieving the telos.